Air classifier



I May 27, 1930- vA. H. sTEBB|Ns 1,759,959 Y,

/Nl/ENTRL'Y n. hun@ ATTORNEY Patented May 27,? 1930 ALBERT 151.v STEBBINS, F LOS GALIO fV AIB CLASSE; i ge,

Application le. April 2, 192@n Serial No, 266,515.

between them, and the side walls' are pro- 'vided with corrugations or ribs that slope downwardly in a direction tovdirect down 1lil wardly the particles that workT4 out of the path of the air into contact with the side walls.

i It is important that the heavier'particles` rather than the iine particles work out of the lpath of the air against the sidel walls, and this is accomplished in vaccordance with the present invention by so constructing and arranging the flutes or corrugations o the side walls that "they will form a tortuous or serv pentine air passage, so that as the materials are carried along this tortuous path by the air the heavier articles will be thrown outwardly a ainstt e side wall by the combined action o momentum and centrifugal force,

while the lighter particles which are aifected to a less degree by these forcesA will remain in the path of the air. s s

The heavier particles as a result of the s eed with which they are carried throu h tiie passage by the air will slide a substantial distance along the downwardy inclined ribs or iiutes upon striking a side wall of the container and this will carry the heavier particles rapidly down into the lower portion of the receptacle to eiect the desired separation.

f desired various grades of the heavier materials that settle out of the air within the classifier may be secured by providing a se-` ries of collecting hoppers along the lower side'of the classifier, and air maybe introduced at a number of points 'lengthwise' of the air classiiier to carry the lighter particles entirely through the classifier.

-sectional view through' aportion of the tor- '.tuous air passa c.

The various features of the inventon a'nd arrangement of parts will be best' understood from the, following description when read in connection with ,the drawings showing one good practical ormof the invention In the drawingsf t n v F ig1 lis a side elevation of the air 'classifier constructed in accordance with the present v invention, parts of Athe classier being shown in'section;

Fig. 2 is a sectional view taken on the line 2"-2 oFigl; 1-

Fig. 3 is a sectional view taken on the line\ 3-3 of F ig. 1; and

Fig. 4 on an enlarged'scale is a horizontal The air classi er forming the subject matter of the present invention may be variously constructed andmay employ a single tortuous air passage as shown, or may be provided with a number of these air passages formed side by side to increase the capacity of the air classifier. Air in most cases will be employed as the carr ing medium for conveying the materials to e-treated through the air classifier, but it will be understood that water or other` fluids may be employed as the carrying medium v In the embodiment of the invention'shown in the drawings the material laden air travels in a horizontal direction through the classifier, but this is not essential in all embodiments of the invention since the air maypass through the air classifier in any desired drection so long as the corrugations or iiutes are disposed at an inclination to the path of the air and extend in avdirection to carry the materials that travelalong the flutes or corrugations out of the path of the air.

In the construction of the invention shown 90 in the drawings the air classier is providedl with the side walls, 10 which are spaced from each other tc form the narrow air passa e 114 between them, and the side wallslO are uted or corrugated as shown'u The walls 10 yat '95 their lower ends are secured to the Hoor plate 12 and at their'upper ends are secured to the cover plate 13. l.

In Ithe construction4 shown 'the left-hand end of the classifier is open to receive air-from ,100

the atmosphere and air is exhausted `from the opposite end of the classifier bythe exhaust fan 14' having the exhaust pipe .15 which leads from the suction side of the fan to the exhaust chamber 16 provided at the rightl hand end of the air classifier. AIt ina-y be desirable to vary the ,volunie of air which enters the inlet endof the classifier and this is accomplished in the construction shown'by providing the classifier with the swinging gate 17 which may be moved towards andfroin the'vixed wall 18' to vary the size of the air inlet opening 19; The mavterials to be treated may be introduced into the air passage 11 near the inlet end thereof by providing the feed hopper y20 having the sliding gate 21`for-regulating the flow of the materials from the feed ho per into the air passage, and these materia s will be picked up by the air and carried Alengthwise ofthe air classifier inthe direction indicated by the arrows. i i

The side walls 11 of the air classifier are corrugated or fluted as shown and these corrugations or flutes are. so arranged that they orm a tortuous or serpentine air passa .throughthe air classitieigvso that as the air -asses along4 this tortuous air passage the eavier particles will work out of the path of the air against theside walls of the container under .the action of momentum and centrifugal force. The centrifugal .force will serve loops or channels 22o tol -throw the heavier particles out into the i the tortuous air passage and the momentum will cause the heavier particles to strike against the side walls instead of following'the tortuous ath Yof the air travelingthrough the classi er.

An important feature of the `present invei'ition resides in the construction of the corrugationsor iiutes of the sidewalls 10 so thatl these corrugations or' flutes extend diagonally of the path of the airand' slope downwardly in a direction to. guidedownwardly the particles that strike against these flutes or cor- 'rugations Due to the speed with which the materials are carried through the classifier by the air the heavier particles-which work out ofthe path of the air will strike against the lflutes or corrugati'ons with considerable force and will slide along thesedownwardly inclined flutes or corrugations a substantial distance. This will serve to ca Y cles downwardly rapidly intonth tion of the classifier.

It ma be desirable to Separate the heavier i materia s' that collect in the lower porion of be done by the classifier into various grades and this may roviding a series of collecting hoppers 23 a ong the ower side of the classifier. In the present construction means is yprovided for admittin air from the atmosphere into the classi er at various points along the same and this is accomplished by .providingthe collectinghoppers 23 with the these parti. e lower porair inlet passage 24 the size of which magi` be f varied as desired by adjusting the sli gates 25. Within eachy hopper 28 is preferably mounted a deflector 26 which serves to direct the air downwardly around the defiector plate as shown so that it willl pass upwardly through the falling materialwith a swee ing action that will cari?I upwardly the er particles that may ten to settle in the hoppers with the heavier particles. The air exhaust chamber 16 is preferably given the tapered construction shown in Fig. 1 to ac-l commodate the volume of the'air which in.-

creases in this chamber from the lower to the upper end thereof, and the materials that settle within this chamber will pass downwardly into the collecting hopper 2 The classifier shown increases height from its inlet to its discharge vend.A This is desirable in many constructions to facilitate expansion of the air as it travels lengthwise of the classifier, which in turn will promote settling of the particles out of the air as they ap-` proach the discharge end of the classifier.

ItI will be seen from the foregoing that the downwardly inclined corrugations or iiutes formed in the side walls 10 'of the classifier perform the double function of working theA heavier materials out ofthepath of the air traveling through the tortuous air passage 11 and of quickly directing these heavier partilof the 'air stream, and means for advancing material -laden air through the passage so that i the heavier particles that work out of the pathA of the air into the channels between the corruations or flutes will be carried by their velocity along the downwardl .inclined channels towards the lower wall o the classifier.

2. An air classifier comprising a container Ahaving substantially vertical side walls disposed in close proximity to each other to form a narrow air passage. between them, means for advancing material laden air through the narrow passage in a horizontal direction, andy the side walls'bein nprovided with ribs or fiutes that extend ownwardlyatnn acute angle to the direction of the air stream through the passage so that theheavier particles that work laterally out ofthe path of the a-ir against the ribs or iutes will be carried 'by their velocity along the downwardly inclined ribs or flutes towards the lower side of the classier. v

t `3; An air classie'r comprisinga container having substantially vertical corrugated side walls arranged to form a narrow serpentine passage between the walls, means for advancing material laden air through the passage, '5 and the corrugations of the side walls-being constructed to slope' downward at an acute angle to the direction of the air stream through the passage so that f the particles that work out of the path of the air against 10 the corrugated sidewalls will be carried by their velocity along the downwardly inclined corrugations towards the lower side of the classifier.

4. An air classifier comprising a container 15 having approximately vertical side4 walls spaced to form a narrow air passage between them, means for advancing material laden air through the air passage, the side walls being provided with diagonal ribs or iiutes` that 20 slope downwardly at an acute angle to the direction of the air stream through the passage so that the particles that work out of the path 'of the air against the ribs or fiutes will be carried by their velocity along the 25 downwardly inclined ribs or flutes towards the lowerside of the classifier, and means for introducing additional air into the container at a plurality of points.

5. An air classifier comprisin a container 3:) having approximately vertical side walls dis- Y posed in close proximity to each otherto form a narrow air passage between them, means for advancing material laden air through said passage, and the side walls of the passage being provided with downwardly inclined ri-bs disposed at an acute angle to the direction of the ail' stream through the paslsage and adapted to defiect downward the traveling particles that strike these ribs t0y o cause these particles to be carrieddownwardly along the ribs by their velocity.'

In testimony whereof, I have signed my name to this specification.

ALBERT H. STEBBINS. 

